Does testosterone build a better athlete?

Testosterone injections can make male rats more aggressive in
marking their territories, cause castrated red deer to grow antlers
and induce female rhesus monkeys to screech like males. In studies
on humans, testosterone injections have increased and strengthened
muscles.

In sports, testosterone shots or creams are supposed to be magic
bullets that spur athletes to train harder, run or bicycle more
quickly, jump higher, swim faster, hit a baseball farther, recover
sooner and, let's not forget, increase sex drive and
combativeness.

Certainly, the idea that taking doses of the hormone gives
competitors an unfair advantage is behind the brouhaha over
Murrieta's Floyd Landis, the 2006 Tour de France winner who French
officials say tested positive for elevated testosterone on the day
of his remarkable comeback during Stage 17. Landis has denied
taking any performance-enhancing substances.

But some leading experts who study testosterone are not
convinced that supplementing the hormone improves endurance or
overall athletic performance. Unlike a hyper-caffeinated sports
drink, the synthetic hormone does not provide an instant jolt, but
works over time to bulk and fortify muscles.

What other effects taking testosterone may have on athletes is
the subject of heated debate.

"A long-term buildup of testosterone would produce results,"
said Allan Mazur, a professor of public affairs at Syracuse
University, who has studied how the natural hormones of college
athletes fluctuate before and after competitions. "But we don't
know the short-term effects of using testosterone on an athlete's
performance, or whether it even has a short-term effect at
all."

Secreted by the testes and adrenal glands, testosterone is the
male sex hormone that generates and maintains secondary sexual
characteristics like a deep voice and body hair. It also plays a
role in body fat, and in muscle size, strength, and function.

Some athletes illegally use anabolic steroids, the
muscle-promoting drugs or hormonal substances that are chemically
related to testosterone, in the form of injections, skin patches,
creams or pills. These steroids can stimulate muscle building. But
they will not transform couch potatoes into pole-vaulters.

"Steroids are not going to take someone without athletic ability
and turn them into a star athlete, or teach you how to swing a bat
and connect with the ball," said Douglas A. Granger, the director
of the behavioral endocrinology laboratory at Pennsylvania State
University. "But if you have a certain athletic presence,
testosterone could take you to the next level."

Steroids first became popular among American bodybuilders in the
1950s after they began to suspect that gold-medal-winning Soviet
weightlifters were using them, sports researchers said. But the
American medical establishment did not believe that supplemental
testosterone could promote muscle growth until the 1990s when
scientists began examining its effects, said Dr. Shalender Bhasin,
a professor of medicine and chief of endocrinology, diabetes and
nutrition at Boston Medical Center.

In 1996, Bhasin published a study in The New England Journal of
Medicine on the impact of testosterone injections, given once a
week for 10 weeks, on healthy adult males. The idea was to see
whether testosterone might be used therapeutically in
muscle-wasting diseases like AIDS. For volunteers who received
testosterone, their triceps and quadriceps became larger and they
had increased muscle strength during bench presses and squats.

"Synthetic steroids take you from being a natural normal male to
being a supermale with muscles that are bigger and stronger," said
Dr. Donald H. Catlin, the director of the Olympic Analytical
Laboratory, a drug-testing facility, at UCLA. "Athletes love to
take steroids because they work."

But do bigger, steroid-enhanced muscles generate big
winners?

"We assume that, if you are stronger, you will perform better,
but that might not necessarily be true," said Michael S. Bahrke, a
steroids researcher in Ellison Bay, Wis., and co-editor of a book
called "Performance-Enhancing Substances in Sport and Exercise."
"For football and baseball players, explosive muscle mass might
relate to more power, but it is difficult to document that it leads
to better performance."

Larger muscles might even be detrimental for certain athletes.
For marathoners, enhanced muscles could put more weight on joints
than they can handle, leading to injuries, Bahrke said.

In addition to joint problems, taking steroids can cause side
effects like oily skin, acne, shrunken testicles, sterility and
male breasts. Synthetic testosterone can also inhibit good
cholesterol, increasing the risk of heart disease.

But withdrawal, which can make some men deflate like used
balloons, may be the most troubling problem. Taking steroids
suppresses men's own natural testosterone production. After
athletes stop taking testosterone, the body may take weeks to
months to return to normal hormone levels.

"In the meantime, you will have decreased muscles and decreased
sexual function, such stressful withdrawal symptoms that many
people go right back on testosterone," Bhasin said.

Because of the possible side effects, doctors rarely experiment
on humans by dosing them with testosterone unless it is for medical
reasons. Without that kind of empirical data, scientists can only
speculate on how testosterone may affect a person's competitiveness
and athletic ability, researchers said. But there are some
intriguing observational data.

Observational studies of humans show that hormone levels may
fluctuate during competitions. For example, Alan Booth, a professor
of sociology and human development at Penn State, has conducted
several studies with Mazur, and with Granger, in which they
measured the testosterone in saliva samples taken from a variety of
college athletes. Their studies found that many male and female
athletes' testosterone levels increased before competitions. After
the competitions were over, among men, the winners' testosterone
levels tended to rise temporarily while the losers' testosterone
tended to drop.

The researchers cannot prove why the hormone fluctuated, but
Booth theorized that post-game testosterone fluctuations may have
originated during ancient tribal warfare, the kind of continuing
life-or-death competition that would require long-term physical and
mental readiness.

"If you win, you know you are going to be challenged again soon,
so higher testosterone would keep you prepared for the next
challenge," Booth said. A dip in testosterone might make losers
disinclined to fight further, he said. "Lower testosterone may keep
individuals who lost and got seriously wounded from engaging in
another immediate battle where they might suffer even more
damage."

But Bhasin said that such testosterone oscillations may play no
role. Testosterone has been shown to rise a little in anticipation
of exertion, like a treadmill run, he explained. "But the
explanations of cause and effect between athletic performance and
testosterone are very weak."

Other researchers have speculated that taking testosterone may
stimulate fine motor skills that improve athletes' hand-eye
coordination or help athletes recover from exertion by increasing
the amount of oxygen in their bloodstreams.

Bhasin's research contradicts some of the locker room myths. In
his own study, the volunteers injected with testosterone neither
experienced improved endurance nor exploded in 'roid-induced rage,
he said.

"There have always been a lot of misconceptions about
testosterone," Bhasin added. "I'm very hopeful that clarity will
emerge, but right now there is a lot of folklore."